Copolymers of 4-methyl-1-pentene with lower 1-olefins



United States Patent 3,457,246 COPOLYMERS OF 4-METHYL-1-PENTENE' WITH LOWER l-OLEFINS James W. Cleary, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware N0 Drawing. Continuation of application Ser. No. 251,036, Jan. 14, 1963. This application Mar. 3, 1967, Ser. No. 620,560

Int. Cl. C08f 15/04, 1/42 U.S. Cl. 26088.2 6 Claims ABSTRACT OF THE DISCLOSURE Solid copolymers of 4-methyl-1-pentene and a lower olefin selected from ethylene and propylene are produced by incrementally adding a plurality of increments of the lower olefin to the reaction phase during polymerization whereby the total amount of lower olefin so added is within the range of from about 0.25 to about 10 parts per 100 parts of said 4-methyl-1-pentene.

This application is a continuation of my copending application Ser. No. 251,036, filed Jan. 14, 1963, now abandoned.

This invention relates to copolymers of 4-methyl-1- pentene with lower l-olefins.

Po1y-4-methyl-1-pentene has been described before but the polymer was found to lack characteristics which are desirable for many applications, particularly the applications requiring that the polymer be soluble in hydrocarbon solvents. In addition, the polymer has a melting point too high generally for melt extrusion. However, the poly- 4-methyl-l-pentene has high resistance against attack by chemical reagents and microorganisms which makes the polymer very desirable and potentially useful. It has also been discovered that copolymers of 4-methyl-1-pentene and higher l-olefins produce a soluble, isotatic hydrocarbon copolymer. However, copolymers of 4-methyl-lpentene with a lower l-olefin have been found to produce a relatively insoluble product.

It is an object of the invention to provide a copolymer of 4-methyl-1-pentene and a lower l-olefin.

It is another object of the invention to provide a copolymer of 4-methyl-1-pentene and a lower l-olefin which is soluble in hydrocarbon solvent.

It is another object of the invention to provide a method for the production of a soluble copolymer of 4-methyl-1- pentene and a lower l-olefin.

It is another object of the invention to provide a copolymer of 4-methyl-1-pentene and a lower 1-olefin having improved elongation characteristics.

These and other objects of the invention will be readily apparent to those skilled in the art from the accompanying disclosure and claims.

These and other objects of the invention are broadly accomplished by preparing the copolymer of 4-methyl-1- pentene and a lower l-olefin by the method comprising polymerizing said 4-methyl-1-pentene under polymerization conditions while incrementally introducing the lower l-olefin at a rate sufiicient to produce a copolymer having an n-he-ptane soluble content of greater than 50 percent when determined as hereinafter described. The expressions polymer and copolymer are used interchangeably herein when referring to the polymer or copolymer of 4-methyl-1-pentene and a lower l-olefin.

It has now been discovered that when the comonomer is incrementally introduced into the polymerization reactor in the presence of 4-methyl-1-pentene the copolymer thus produced surprisingly has an increased normal heptane solubility as compared to a copolymer produced by Patented July 22, 1969 the simultaneous addition of the comonomer and 4- methyl-l-pentene to the reactor or as compared to a copolymer produced by the introduction of the 4-methyll-pentene in one stage into the reactor containing the comonomer.

The invention is broadly applicable to the polymerization of 4-methyl-1-pentene and lower l-olefins. Particularly preferred mono-l-olefins are ethylene, propylene, l-butene, and l-pentene. Even more preferred are ethylene and propylene.

These polymers are prepared in the presence of a catalyst active for the copolymerization of the 4-methyl-1- pentene and the comonomer and the invention is not limited to a particular catalyst system. One suitable catalyst is prepared by admixing at least two essential components, one of said components being (1) a metal compound selected from the group consisting of Groups 1V, V, VI and VIII metal compounds and another of said components being (2) selected from the group consisting of organometal compounds, metal hydrides and metals of Groups I, II, and IH. A suitable catalyst system comprises a dialkylalurninum halide and a titanium halide, e.g., a dialkyl aluminum chloride and titanium tn'chloride. One presently preferred catalyst system comprises a diethylaluminum chloride and the reaction product of aluminum and titanium tetrachloride. Said reaction product can be represented approximately by the empirical formula AlTi Cl In one embodiment presently preferred, the polymerization is conducted in the presence of a small concentration of elemental hydrogen, preferably in the range of 0.25 to 2.5 mol percent of hydrogen based on 4-methyll-pentene.

The ratio of the catalyst components employed is variable rather widely depending upon the particular monomers employed and the operating conditions. The mole ratio of the Group I, II or III metal'or metal compound to the Group IV, V, VI or VIII metal compound is usually in the range of 1:1 and 10:1 with the preferred range of 2:1 and 5:1. The concentration of the catalyst in the polymerization zone is usually in the range of 0.01 to 5 weight percent based on the total monomers charged to the zone although a lesser or greater amount can be employed.

In a preferred method for the preparation of the soluble 4-methyl-1-pentene copolymer, the catalyst, hydrogen and the 4-methyl-1-pentene monomer are charged to the reactor and the polymerization is initiated, for example, at a temperature in the range of between and 175 F. The comonomer, for example propylene, is then introduced in increments beginning preferably 5 to 30 minutes after initiation and preferably continuing at 5 to 30 minute intervals for the entire polymerization period, usually from 2 to 5 hours. The size of the increments will vary depending upon the total charge of comonomer, the polymerization conditions, the catalyst and the product desired but generally the total charge of the comonomer, such as propylene, will be divided into increments of not'less than 2 nor more than 60, preferably of approximately equal fractions.

The amount of the lower l-olefin will vary over a wide range depending upon the desired polymer product but preferably the lower l-olefin employed in the polymerization step is in the range of from about 0.25 to about 10.0, preferably from about 0.3 to 5.0, weight parts per parts of 4-methyl-1-pentene.

It has been found that a major portion of the copolymers of 4-methyl-1-pentene and the lower l-olefin produced by the method of this invention are soluble in organic solvents such as diethyl ether, chloroform, carbon tetrachloride, cyclohexane, benzene, toluene, xylene,

3 4 chlorobenzene, tetrachloroethane, tetrahydrofuran, as end of the ISO-minute reaction period, the unreacted well as a number of other similar solvents. A particularly monomer was vented and the reaction quenched with preferred solvent is normal heptane. The term soluble methanol. The polymer was removed from the reactor, or n-heptane-soluble content means that the polymer chopped in a Waring Blendor in the presence of methacontains a major portion (50 percent or more) of a matenol, collected on a filter and dried in a vacuum oven at rial which is soluble in normal heptane as further de- 5 approximately 80 C. Run No. 1 was a control run in scribed in footnote (1) in Table I of Example I. Preferwhich there was no addition of propylene and Run No. 2 ably, the normal heptane-soluble content of the copolywas a control run in which the reactor contained an origmers of this invention is greater than 70 weight percent. inal atmosphere ofpropylene of about 1.9 grams. Physi- Generally, the heptane-soluble-content is in the range of 10 cal properties were determined. Data on these runs and 50 to 95, more preferably 70 to 90, weight percent. physical properties are presented in Table I.

TABLE I [4-mothyl-l-pentene and propylene copolymer-s] Pro ylene p Solubles 1 Interval Increment, or times, No. of Total, Conversion, Diethyl Elongation, Density, Shore D gms. minutes increments gms. percent n-Heptane ether percent gmJ cc. hardnesss a l The heptane or ether-soluble content was determined by extraction Extraction time was hours. The extracted polymer was dried at 110 C. oi the polymer with boiling pure-grade solvent or ether in an ASTM for 2 hours prior to weighing the solvent-insoluble residue. Hcptane or rubber extraction apparatus (see ASIM D-494-46, Fig. 1). This is a ether soluble=100 (heptane or ether insoluble). modified Soxhiet apparatus in which the extraction cup and thimble are 2 Determined by ASTM D-63861T. immersed in the vapors from the boiling solvent to maintain the tempera- 3 Determined by ASTM Dl706 6l. ture of the condensed extracting liquid at or near the boiling point. 4 1.9 grns. propylene present in atmospherc.

In addition, it has been found that the copolymer thus These data indicates that the incremental add1t1on of produced is less brittle than that produced by heretofore propylene to a reactor containing 4-methyl-1-pentene unproposed methods. Preferably, the copolymer of this inder polymerization conditions produces a copolymer havvention has an elongation of at least 40 percent, and even ing a normal heptane-soluble content in excess of about more preferably at least 100 percent. Generally, the clon 80 percent and considerably greater than in a similarly gation is in the range of 40 to 200 percent, preferably 40 produced 4-methyl-1-pentene polymer (Run 1) or a coto 160 percent. polymer of 4-methyl-l-pentene and propylene where the In general, it has been found that the content of the npropylene was charged prior to initiation of the polymeriheptane insoluble polymer decreases as the amount of zation (Run 2). In addition, the incremental addition lower l-olefin per increment was increased at the same method produces a polymer having an elongation of greattime interval. Also, these values increased with an iner than 100 percent, compared with 1-3 percent for either crease in the time interval between addition of the same the 4-methyl-1-pentene polymer or a copolymer of 4-methamount of lower l-olefin in each increment. Tensile yl-l-penten and propylene where the propylene was strength and elongations were more variable but tend to charged prior to initiation of the polymerization. support these trends.

The products of the invention are useful for the fabri- EXAMPLE II cation of molded articles, films, fibers, textiles, and the like A series of runs was made in the same manner as The invention is best illustrated by the following examdescribed in Example 1 except that the comono-mef ployed was ethylene. The results are tabulated in Table II.

TABLE I1 [4-methyl-1-pentene and ethylene copolymers] Ethylene Percent Solubles Interval Run Increment, of time, No. of Total, Conversion, Dieihyl Elflngatlon, y, h r D gms. minutes increments gms. percent n-Heptane ether percent gmJce. hardness 3 0 0 51 1 6 8. 1 1 0. 3337 75 0. 062 5 30 1. s7 27 87. 0 69. 1 40 0. 8491 38 0, 12 5 30 75 24 74. 1 57. 9 150 0. 8635 2a 0. 25 5 a0 7. 5 30 73. s 55. 0 95 0. 8746 25 0. 062 10 15 0. 94 1s 80. 7 62.7 0. 8626 32 1 Footnote 1, Table I. 9 Determined by ASTM D-633-61T. 3 Determined by ASTM D-1706-61.

EXAMPLE I These data indicate that copolymers of 4-methyl-l-pentene and ethylene are producible which have normal hep- A series of runs was made in which 4-rnethyl-l-pentene tane-soliible contents greater than about 74 percent by the and propylene were polymerized in the presence of a incremental addition of ethylene whereas the heptanecatalyst system comprising diethylaluminum chloride and 5 soluble content of the 4-methyl-l-pentene polymer was the reaction product of aluminum and titanium tetraonly 10.6 percent. Further, the copolymer thus produced chloride containing 24.5 weight percent titanium and 71.2 is considerably less brittle as evidenced by an elongation percent chloride. These runs were made in a 1-liter stainof 40 percent or greater compared with 1 percent for the less-steel stirred reactor using 150 grams of 4-methyl-l- 4-methyl-l-pentene polymer. pentene, l millimole of aluminum titanium tetrachloride 7 I claim: reaction product, 3 millimoles of diethylalurninum chlo- 1. A solid copolymer of 4-methyl-1-pentene and alower ride, and 44 miliimoles of hydrogen. The temperature olefin selected from ethylene and propylene fonned by was maintained at C. During the polymerization, small subjecting 4-methyl-l-pentene to polymerizing conditions, amounts of propylene were incrementally injected at regand adding thereto, during the course of said polymerizaular intervals as shown in the following Table I. At the 75 tion, a plurality of about equal increments of said lower olefin, the total amount of said lower olefins so added being from about 0.25 to about part per 100 parts by weight of said 4-methyl-l-pentene, all of said 4-methyl-lpentene having been added prior to said lower olefin addition.

2. The copolymer of claim 1 wherein said lower olefin is added in from 2 to 60 incremental portions, said increments are added at intervals of 5 to minutes, the amount of said lower olefin so added is from about 0.3 to about 5 parts per 100 parts of said 4-methyl-lapentene, said polymerization occurs at a temperature from about 75 to about 175 P. so as to form a copolymer having an n-heptane soluble content of greater than about percent.

3. The copolymer of claim 2 wherein said lower olefin is ethylene and said copolymer has an elongation of at least 40 percent, density at least .8491, and Shore D hardness between about 25 and about 38.

4. The copolymer of claim 2 wherein said lower olefin is propylene and said copolymer has an elongation of at least about 100 percent, density at least .8393, and Shore D hardness between about and about 60.

5. The copolymer of claim 1 wherein said polymerization is conducted in the presence of 0.25 to 2.5 mol percent of hydrogen based on 4-methyl-1-pentene.

6. The copolymer of claim 1 wherein from 0.3 to 5 References Cited UNITED STATES PATENTS 3,029,215 4/1962 Campbell 260-88.2

FOREIGN PATENTS 856,733 12/1960 Great Britain.

OTHER REFERENCES Margenson et al., Introduction to Polymer Chemistry (1967) pp. 9-11.

JOSEPH L. SCHOFER, Primary Examiner L. EDELMAN, Assistant Examiner US. Cl. X.R. 

